In certain medical procedures, such as blood vessel embolization, it may be desired to inject particles into the body. Such a procedure may be a minimally invasive alternative to surgery. One purpose of embolization is to prevent blood flow to an area of the body, which may effectively shrink a tumor, such as a uterine fibroid (leiomyoma). Further, such procedures may also shrink other kinds of tumors or block blood flow to or within an aneurysm or arteriovenous malformation. Embolization may be done by injecting blocking particles into a blood vessel.
Such procedures may be carried out as an endovascular procedure, such as by a radiologist in an interventional suite. Some patients may have the treatment carried out with little or no sedation, although this may depend on the organ to be embolized.
Access to the organ in question may be acquired by means of a guidewire and catheter. The position of the correct artery or vein supplying the undesired tissue in question may be located by X-Ray images. These images may then be used as a map for the radiologist to gain access to the correct vessel by selecting an appropriate catheter and/or wire, depending on the shape of the surrounding anatomy.
The blocking particles may be mixed into a saline solution; additionally, in some instances, a contrast agent may be added (for example, to make the mixture opaque to X-rays). The blocking particles may be of certain sizes, such as between 0.1 mm and 1 mm, and may be configured to block a blood vessel at a particular diameter. Such particles may tend to settle quickly out of the mixture, as the particles may be denser than the liquid carrying them, or they may float as the particles may be less dense than the liquid carrying them. Settling or floating may result in an uneven concentration of particles during the injection. In some instances, the settling or floating may occur in as little as a few seconds. It may be difficult or problematic to continually shake the syringe used for injection, however, as the entire procedure may be performed in a few seconds and the doctor has to concentrate on injecting the correct amount. Thus, it is desired to have a syringe configured to keep the particles uniformly dispersed in the carrying solution regardless of delays in the injection process or speed of the injection. Additionally, since the syringes used may be low-cost disposable items, in some embodiments, the device used to keep the particles uniformly dispersed may also be very low-cost and/or disposable. Some embodiments of mixing syringes within the scope of this disclosure may comprise the following attributes:
A. Ability to be re-filled multiple times during a procedure. Thus, in certain embodiments, the mixing syringe may not comprise certain single-use designs, which include rupturing of a membrane to allow mixing.
B. Generate a strong mixing action, for example, by creating a vortex or a jet-like liquid flow pattern in the mixture.
C. Use the minimum modification to a standard syringe.
Certain mixing syringes, such as disclosed in U.S. Pat. No. 7,883,490, are designed to mix together two materials stored separately in two compartments. They are not designed to stir up a pre-mixed solution. Additionally, certain syringes which may be designed to stir up embolization mixtures, such as disclosed in U.S. Patent Application Publication No. 2009/0247985, are needlessly and highly complex. Also, existing mixing syringes are not designed to be filled with the pre-mixed solution just before use. This filling step may be part of embolization procedures, however, as the correct volume and ratio of saline, particles and contrast agent may be customized to the procedure by the doctor. A mixing syringe according to the present disclosure, may allow filling and injecting at any time, while keeping the solution stirred up during injection. Further, in some embodiments, a mixing syringe according to the present disclosure may be re-used several times during a procedure, if a practitioner desires to inject more particles. In some embodiments, a mixing syringe according to the present disclosure may be manufactured out of a standard syringe, which may be a low-cost item.